Air-brake



(No Model.)

J. M. MAXWELL.

.AIRl BRAKE.

ATTORNEYS.

UNITED STATES PATENT OFFICE.

JAMES M. MAXXVELL, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO HIM- SELF, AND MICHAEL M. COMERFORD, OF FAIRMONT, TEST VIRGINIA.

AI R-BRAKE.

SPECIFICATION forming part of Letters Patent No. 405,968, dated June 25, 1889.

Application filed April 25, 1888. Serial No. 271,777. (No model.)

To all whom, it may concern.:

Be it known that I, JAMES M. MAXWELL, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and Improved Air-Brake, of which the following is a full, clear, and exact description.

The invention relates to air-brakes such as described iii Patent No. 207,126, granted to me August 20, 1878.

The object of the invention is to provide a new and improved air-brake which is simple and durable in construction and very effective in operation.

The invention consists of certain parts and details and combinations of the same, as will be fully described hereinafter, and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure l is a sectional side elevation of the improvement. Fig. 2 is a side elevation of a reversing-valve. Fig. 3 is a cross-section of the same 011 the line c of Fig. 2, and Fig. i is an end elevation of the sleeve.

The auxiliary reservoir A is located under the cars, and is provided with a pipe D, containing a check-valve Il' and connected with the air-supplypipe C, running under the several cars, and having valves C', for establishing connection between the several oars and shutting off the connection whenever desired. The forward end of the 'pipe C leads to the engineers valve D, Yfrom which leads the pipe E, connecting with the main reservoir. The plug D' in the engineers valve D is operated by the usual handle DE, and serves to establish a connection between the pipes C and E, or to disconnect the same, so as to admit air to or out it oit from the main supply-pipe C from the main reservoir. The plug D' is also adapted to establish a connection between the pipes C and I1, in the outer end of which pipe F is held a valve F', and the said plug D' can also be turned to establish a connection between the pipe C and the pipe F2, leading to the outside air.

From the auxiliary reservoir A leads a pipe G,which connects with the air-cl lest Informed on one end ot' the cylinder Il. In the chest:

H' is held to slide a slide-valve I, connected with the piston-rod J' of the piston J, mounted to slide in and with a sleeve K, held in the said cylinder ll'. At the rear end of the 55 sleeve K is secured a transverse bar K', in which screws a bolt K2, its head Iitting into a correspoiidingly-shaped aperture L', formed in the screw L, screwing in the head of the cylinder ll'. At the inner end of the cylinder 6o lI is formed an outlet-opening 112, so as to permit waste air leaking through the chest lI', the piston J, and sleeve K to escape.

The slide-valve I is adapted to operate over the supply-port a for applying the brakes, over the supply-port l) for releasing the brakes, and over the port c for exhausting the air alternately from the ports a and l). The ports a and b lead to the straight ports d and e, formed in a valve N', mounted to turn in an 7o olisct directly below the chest ll'. Theports a and l) can also connect with the spiral. groo ves fand g, formed in the periphery of the said valve N and serving to reverse the action of the brake, as hereinafter more fully described.

The ports il and c and the channels f and g are adapted to connect at their lower ends with the pipes O and I, having the branch pipes O' OZ and I" P2, respectively, leading 8o into the auxiliary brake-cylinders Q, and Q', respectively. In the pipes O2 and I2 are held the inwardly-opening valves O3 and I, respectively. The cylinder Q is somewhat larger in diameter than the cylinder (2', and S5 the said cylinders contain the pistons It and R', respectively, connected with each other by a piston-rod R2, which carries an arm S, connected with the brake-rod T, and the said piston-rod R2 also operates on the lever S', 9o connected with the brake-'rod T', extending in an opposite direction 'from the brake-:red T to the other end of the car. The cylinder Q and its piston R serve to apply the brakes, and the cylinder Q' and its piston R' are used 9 5 for releasing the brakes.

From the cylinder Il leads a pipe U,which connects with the lnain supply-pipe (l.

On the outer end of the piston-rod J' is formed a pin J2, against which presses a roo spring V, held in a recess in a screw lV, screwing in the head ol' the chest ll'.

the cylinder I-I can pass through the pipe U' into the pipe C, and from the latter to the pipe F and out through the pop-valve F'. The air-pressure in the cylinder H is thus somewhat reduced, so that the air in the auxiliary reservoir A forces the piston-rod J' and its piston J outward until it strikes,

against the screw K2 of the sleeve K, when it will be arrested, owing to the fact that the pressure against the sleeve K is now greater than the pressure against t-he piston. Vhen the piston has moved to the position just described, the valve I has been moved so that the port b connects with the port c, and the port a is partially uncovered and in communication with the chest I-I'. The air from the auxiliary reservoir A and the chest H' can now pass through the ports a and b into the pipe O, and from the latter through the branch pipe O2 and the valve O3 inthe end of the cylinder Q. The pressure of the air thus admitted into the cylinder causes the piston-rod R to move outward, whereby the brakerods T and T' are moved inward toward each other and the brakes are applied slightly. Then the engineer desires to apply the brakes more fully, he turns the handle D2 until the plug D' establishes a connection between the pipes C and F2, so that still more air can escape from Athe cylinder H through the pipe U and the said pipes C and F2. The pressure in the cylinder I-I is thus so reduced that the pressure in the auxiliary reservoir A forces the piston-rod J', the piston J, and the sleeve K until the screw in the sleeve strikes against the screw in the end of the said cylinder, when the valve I will be moved sul'liciently to wholly uncover the port a. `The air then passing through the ports a and cl and into the pipe O passes from the latter through the pipe O' and the pipe O2 into the cylinder Q and forces the piston R to the end of its stroke, whereby the other piston R' forces the air from the cylinder Q' to exhaust through the pipe P' into the pipe P, and from the latter through the ports c and b into the exhaust-port c. The valve P3 closes at the inward motion of the piston R', whereby an air-cushion is formed at the end of the cylinder Q. It will thus be seen that the sleeve K serves as a means for arresting the piston J, and thereby preventing the valve I from being moved so as to wholly uncover the port a when it is desired to apply the brake lightly.

It is understood that when the engineer changes the position of the plug D', so as to establish connection between the pipes F and F2, the check-valve B' in the short pipe B seats itself and prevents an escape of ai r from the auxiliary cylinder A to the pipe C.' When the engineer desires to release the brakes, he throws the arm D2 into the position shown in Fig. l, so as to establish a connection between a pipe C and the pipe E leading to the main reservoir. The air can then pass through the pipe U into the cylinder H and force the piston J and sleeve K inward, so that the slidevalve I again assumes the position shown in Fig. l, whereby the air under full pressure from the main reservoir passes through the auxiliary reservoir A and the pipe G into the chest H', and from the latter through the ports ZJ and e to the pipe P, and through the pipe P2 and the valve P3 to the end of the cylinder Q'. The pressure of the air acting against the piston R' forces the same outward, whereby the brakes are released. As soon as the piston R' has moved a short distance in the cylinder Q' the other pipe P' also opens into the said cylinder Q. The air in the cylinder Q is expelled through the pipe O' the pipe O, and the ports d and a into the exhaust-port c. The valve Og closes at this inward movement of the piston R, so that an air cushion is formed as soon as the piston R has Vclosed the opening of the pipe O'.

The spring V is for the purpose of applying the rear brakes in a train first. This is done by increasing the tension of the said spring V on the rear cars of the train by screwing the screw W inward, so that the piston J and its piston-rod J move sooner than the same devices on the other cars. In order to use direct air, it is necessary to give the valve N a quarter-turn, so as to disconnect the ports CZ and e from the ports a and b and connect the spiral grooves f and g with the ports a and b and with the pipes O and P. It will be seen that the port l) is connected by the groove g with the pipe O, and the port a is connected by the groove f with the pipe P. As the auxiliary reservoir A is charged with air and the pipes C and U and the cylinder H are without air, the piston-rod J of the piston J will be driven outward, so that the slide-valve I' uncovers the port a and the air can pass to the cylinder Q' in order to release the brakes. In order to apply the brakes, the pipe C is charged so that the piston J is moved inward, whereby the slide-valve I uncovers the port ZJ and the air can now pass through the groove g to the pipe G, and from the .latter to the cylinder Q, as above described, thus applying the brakes. Thus it will be understood that by changing the position of the valve N direct air can be utilized for applying and releasing the brakes.

The valve N may be operated, as above described, from the top of the car by any suitable device, preferably, however, by the means shown in Fig. l, in which the valve N is connected with the rod N', leading to one end of the car, and provided at its outer end with a crank-arm N2, pivotally connected by the link N3 with the lever N, mounted on top of the car. Vith this arrangement the operator can ICJ IIO

apply the brakes independently of the engineers valve.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

l. In an air-brake, the combination, with a cylinder connected with the inain supplypipe, of a sleeve held in the said cylinder, a screw for regulating the throw of the said sleeve, and a piston connected with a slidevalve for operating the brakes, the said piston being held to slide in the said sleeve, substantially as shown and described.

2. In an air-brake, a cylinder connected with the main air-pipe, an air-chest held on the said cylinder, and an auxiliary reservoir connected by a pipe having a check-valve JAMES M. MAXWELL.

Witnesses:

THOMAS MCCAFFREY, JAMES MGCAFFREY. 

